feat(cli+templateengine+deploymanager): resolve follow-ups #4/#5/#6/#8 — CLI ergonomics + structured deploy validation error

Closes the four remaining items in the 2026-06-24 template-inheritance/CLI
follow-up tracker.

#4 — CLI `instance set-bindings` can now set DataSourceReferenceOverride.
  `--bindings` accepts an optional 3rd element per entry:
  [attributeName, dataConnectionId, dataSourceReferenceOverride]. A string
  sets the override; a JSON null or an omitted 3rd element leaves it unset
  (template default). TryParseBindings accepts 2- or 3-element entries and
  rejects a non-string/non-null 3rd element or 4+ elements with a clean
  error. Previously the CLI sent the override as null and silently wiped any
  existing one (only a raw POST /management could set it).

#5 — `template update` is partial, not full-replace (fixed server-side so all
  clients benefit). UpdateTemplateAsync now uses leave-unchanged semantics:
  a null description keeps the stored value (pass "" to clear); a null
  parentTemplateId keeps the existing parent. Parent stays immutable — a
  non-null differing value is still rejected — but omitting --parent-id is
  now a no-op instead of failing every derived-template update.

#6 — compact `template list`/`get` table output + `--detail`. Table output is
  now id/name/description/parent/derived + member counts (#attrs/#alarms/
  #scripts/#comps/#nativeAlarms) via TemplateTableProjection, fed through a
  new optional tableProjector seam on CommandHelpers. `--detail` restores the
  full dump. JSON output is left untouched (always full) so machine consumers
  are unaffected — the projector only runs on the table path.

#8 — structured deploy-time validation error. New ValidationResult.SummarizeErrors()
  (Commons) returns a grouped, capped summary: leading total count, one line
  per ValidationCategory, and a per-module rollup (canonical name up to its
  last dot) with counts + "... and N more module(s)" caps. DeploymentService
  uses it for the "Pre-deployment validation failed" message and logs the full
  per-entry list via LogWarning. Replaces the flat semicolon-joined dump that
  became a wall of text for instances with 50-194 unbound attributes.

Tests: +8 Commons (SummarizeErrors), +8 CLI (4 binding 3-element / 4 table
projection), +2 net TemplateEngine (partial-update). Affected suites green:
Commons 587, CLI 341, TemplateEngine 447, DeploymentManager 101,
ManagementService 230, CentralUI 866; full solution builds 0/0.

Docs: Component-DeploymentManager.md "Validation Error Reporting"; CLI README
(set-bindings 3-element form, template update leave-unchanged, list/get
--detail); UpdateTemplateCommand doc; known-issues tracker #4/#5/#6/#8 resolved
(all 8 items now closed).

docs/requirements/Component-DeploymentManager.md

@@ -64,6 +64,19 @@ flowchart TD
     class step4 start
 ```
 
+### Validation Error Reporting
+
+When step 2 fails, the returned error is a **grouped, capped summary** rather than a flat
+semicolon-joined dump (followup #8). `ValidationResult.SummarizeErrors()` (Commons) leads
+with the total error count, then lists one line per `ValidationCategory`; within a
+category, entity-scoped findings (notably the unbound connection-binding case, which can
+produce 50–194 entries for a richly data-sourced instance) are rolled up by **module** —
+the attribute's canonical name up to its last dot — with per-module counts, and the breadth
+is capped with a `… and N more module(s)` suffix. The complete per-entry list remains on
+`ValidationResult.Errors` and is written to the deploy log (`LogWarning`) so operators can
+still see every clause when needed. This keeps the UI/CLI failure toast scannable while
+preserving full detail for diagnosis.
+
 ## Deployment Identity & Idempotency
 
 - Every deployment is assigned a unique **deployment ID** and includes the flattened configuration's **revision hash** (from the Template Engine).